Can you add a screenshot and try to mark with some color what/where you don't see something? Maybe view menu (press alt button on your keyboard if you don't see that menu), toolbars sub-menu - composition toolbar is not checked ?

Hi there " FfTh202009 " --good morning ( your reply sent 7.25 am - your time) Wow , that was quick -- have never explored " Screenshot "before -- have spent the last half hour " boning up " on it -- am now , I think , a bit more learned !! Am in Adelaide , South Australia ( would have been about 12.30 am here when I posted my enquiry. Can't believe that the attached " screenshot " has actually produced the whole of the missing top line of the ribbon -- believe that would be nothing to do with what was showing on my screen , but what was actually the full contents of the actual " page " -- I had managed to get the " X " icon in the top RH corner take on a red colour, the bottom of it , just protruding  !! So , I gather I will have to work on screen resizing , to solve my dilemma  ?? !! Your comments will be most welcome -- and it is almost like I have a new toy , now that I am using Thunderbird. Cheers , Neville

Hi there, :) Actually it's 7PM now in Romania, from where I am :) I've cropped your screenshot and if it's about the tabs - I've marked them with green - then you do have many of them and you should close them one by one so you can see new "tabs". Though, you might think to set Thunderbird to open the mails messages in a new windows (instead of tabs) - might be more easy for you to work with them.

From the Menu Bar select Tools-Options-Display-Advanced Select Open messages in a New Window It takes a double click to open a message in a tab or window. If you have the Messages Pane turned on a single click will display the message there. F8 toggles the Message Pane on and off.

All the best!